Applicant has invented several new interventional procedures wherein channels (e.g., bloodflow passageway(s)) are formed between blood vessels, and between blood vessels and other target structures, using transluminally advanceable catheters. These new procedures include novel percutaneous, transluminal techniques for bypassing obstructions in coronary or peripheral arteries through the use of the adjacent vein(s) as in situ bypass conduit(s), and other means of revascularizing oxygen starved tissues or delivering therapeutic substances to vessels, tissue and other organs. These procedures are fully described in U.S. Pat. No. 5,830,222 and in U.S. patent application Ser. Nos. 08/730,496, 09/048,147 and 09/048,147. Some of these procedures may be performed by a venous approach, such as vein-to-artery wherein a tissue penetrating catheter is inserted into a vein and the desired arterio-venous passageway is initially formed by passing a tissue penetrating element (e.g., a flow of energy or an elongate penetration member) from a catheter, through the wall of the vein in which the catheter is positioned, and into the lumen of an adjacent artery. Alternatively, some of these procedures may be performed by an artery-to-vein approach wherein the catheter is inserted into an artery and the desired arterio-venous passageway is initially formed by passing a tissue penetrating element (e.g., a flow of energy or elongate penetration member) from the catheter, through the wall of the artery in which the catheter is positioned, and into the lumen of an adjacent vein. Both approaches have been previously described in U.S. patent application Ser. No. 08/730,327. In addition, it may be advantageous to direct a penetrating element directly into other anatomical structures such as the myocardium, pericardium, chamber of the heart or other organs as described in U.S. patent application Ser. No. 09/048,147.
Different considerations and limitations may apply, depending upon which of these approaches (the “vein-to-artery approach, the “artery-to-vein” approach, or vessel to other anatomical structure) is being used or, more generally, the size and contour of the blood vessel lumen in which the operative catheters are to be placed, and the distance and/or angle between the vessels or other target. This is due in part to the fact that, in the heart as well as in other areas of the body, adjacent arteries and veins may be of significantly different diameter and significantly different dilatory capability. In addition, depending on the procedure to be performed, for example, such as the desired angle of channel creation between blood vessels, one approach may be preferred over the other, to promote, among other things, blood flow channels that encourage non-turbulent blood flow. Also, the consequences associated with causing temporary complete obstruction of a vein may be significantly less than the consequences of causing temporary complete obstruction of an artery. Thus, it is desirable to devise tissue penetrating catheters of the above-described type that are sized, configured and/or equipped differently for use in blood vessels of different sizes, shapes and in connection with different types of pathology.
Moreover, it is desirable for tissue penetrating catheters of the above-described type to be constructed and equipped for precise aiming and control of the tissue penetrating element as the tissue penetrating element passes from the catheter, through at least the wall of the blood vessel in which the catheter is located, and to the target location. Such aiming and control of the tissue penetrating element ensures that it will create the desired penetration tract at the intended location with minimal or no damage to surrounding tissues or other structures.